Test

Add missing generic on `Factory` subclasses #639

Job	Run time
Python 3.8, Database sqlite	1m 37s
Python 3.8, Database postgres	1m 26s
Python 3.9, Database sqlite	1m 33s
Python 3.9, Database postgres	1m 33s
Python 3.10, Database sqlite	2m 25s
Python 3.10, Database postgres	2m 26s
Python 3.11, Database sqlite	1m 41s
Python 3.11, Database postgres	1m 47s
Python 3.12, Database sqlite	1m 40s
Python 3.12, Database postgres	1m 20s
Python pypy-3.9, Database sqlite	3m 21s
Python pypy-3.9, Database postgres	2m 50s
Python pypy-3.10, Database sqlite	3m 27s
Python pypy-3.10, Database postgres	2m 57s
	30m 3s

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